I swapped a 2002 5.3 into my 91. I used a painless harness set up for dual fans. Each fan is wired through a relay and is fused. The fans are from a 2006 Silverado. Once the AC kicks on, a fan comes on (like it's supposed to). The voltmeter begins to drop and heads south. Once the second fan comes on, the gauge drops further settling just north of the red warning indicator on the gauge (factory needle style gauges). Battery is new Optima, alternator is new and a 270 amp unit and I have done the Big 4 upgrade with 1/0 wire. Any help is appreciated to find out how to fix the voltage drop. Stereo is approx. 50 watts no amp. Also this condition occurs whether the lights are on or not (HID conversion)
Thank you.